Hello SommyJo,

 The 2900 power supply subsystem consists of one or two AC-DC power supplies in a 1+1 redundant configuration connected directly to the planar.  The base redundant system will utilize two hot-plug 930 W power supplies in a 1+1 configuration. The system may be purchased with a single power supply as a non-redundant configuration.

Example PSU Configuration: The Redundancy Mode depends on the server chassis and how many PSUs are installed. Here is an example of a server with dual power supply configuration.

• Grid Redundant: In grid redundant mode with the hot spare feature disabled, the power output is distributed equally across both power supplies. However, if a single PSU fails, we drop down to just 475W. This is also referred to as 1+1 Configuration.
• • Extended Power Range limited to single PSU capability.
  • EPR = 495W + 75W = 570W.
  • Full performance while redundant due to load sharing.
• Not Redundant: Also known as  2+0 configuration by adding both power supplies together to create 1140W (2x 570W). However is a single PSU fails, we drop down to just 570W.
• • Extended Power Range includes capability of both PSUs.
  • EPR = (495W + 75W) + (495W + 75W) = 1140W.

PowerEdge PSU: How to troubleshoot a Server Power Supply Unit : https://dell.to/3C8rlqT

Thanks for the answer and the explanation of how redundancy works.

But my problem remains.
Why do I measure a load with one PSU and double the load with two PSU if the server configuration remains the same with the same number of CPUs, memory and disks?

Hello SommyJo,

It may have a problem with one of the power supplies, the power distribution board, the system board, or third party parts.

Try using the each PSU by itself and test results, swap slots. Does the issue follow the PSU? If you are still connected to a UPS you may try direct to A/C outlet and test.

Make sure the system firmware, such as BIOS, BMC, backplane, hard drives, all hardware components are up to date.

Are the PSU identical? What is their DP/N (Dell part number)

Enter the BMC/DRAC configuration utility with + during POST and check System Event Log for any errors or faults.

Test in a minimum to POST configuration and add parts back a little at a time until you find faulting component

The minimum components to allow the PowerEdge™ 2900 to complete POST are:

System board

Processor (with heatsink) in socket 1

One stick of memory in slot 1

1 power supply

Power distribution board

Control panel (to turn on system)

The two PSUs are of the same model (7001049-Y000).
They are connected to a power strip (with voltage meter) connected to the A / C outlet.
The BIOS is 2.5.0.
I downloaded PE2900_BIOS_WIN_2.6.1.EXE, but I didn't understand how to install it. At this time the server does not have an operating system installed.

Hello SommyJo,

You mentioned it is recovered. Can you let me know the history of the 2900? 

Things like when it was last working, anything that was changed after that? Any additional information about the server you can provide.

What did you find in the BMC/DRAC configuration utility with + during POST and check System Event Log?

What results did you get with minimum to post configuration?

For this generation of server I'll recommend to use our SupportLive tool for troubleshooting.

Run Diagnostics and Updating firmware: Make a bootable image that includes the SLI tool

Version 2.x for PowerEdge 9G to 11G  SLI 2.2 ISO Download  - https://dell.to/3Cqu2o8

User guide: -   https://dell.to/3jywDDG

• Creating a bootable support live image DVD on systems running Windows  page 10
• Running the gui-based 32-bit diagnostics page 13
• Starting Dell OpenManage Server Update Utility page 22 to update firmware.

Download Dell Server Update Utility, v.14.12.200.61 https://dell.to/3fWJnmT

Or you may choose to install an OS and run updates from the OS.

I bought it used for little money. I don't know his story.
It is for a test environment, not a production environment. If two power supplies cause me problems, I turn one off.

The System Event Log has been cleared, now there are only these two messages all repeating:

• Storage ROMB Battery: Battery sensor for Storage, failed was asserted
• Drive Slot 6: Sensor, drive fault was asserted.

In fact the disk #6 is reported failure in the management of the RAID

I will try to install the BIOS with the links you pointed out to me.

For the moment, thank you